1. Field of the Invention
The present invention relates to a complex for cancer cell chemotherapy and, more particularly, to a HER2 aptamer-anticancer drug complex for chemotherapy of cancer cells, which includes a nucleic acid aptamer specifically binding to HER2 and an anticancer drug linked with the nucleic acid aptamer, so that HER2-positive breast cancer cells are selectively targeted and killed.
2. Description of the Related Art
Breast cancer is cancer that frequently occurs in women, and many techniques for the accurate diagnosis and treatment of breast cancer are being developed. Typical methods for cancer treatment include surgery, radiation therapy, and chemotherapy, one or more of which may be utilized to treat cancer. Specifically, surgery is a method of removing almost all diseased tissue, and is very effective at removing tumors from specific regions, for example, the breast, colon and skin, but is unsuitable for the treatment of tumors in some regions, such as the spine, or for the treatment of dispersed tumors. Also, radiation therapy is useful in the treatment of acute inflammatory diseases, benign or malignant tumors, endocrine dysfunction, and allergic diseases, and is typically effective at treating malignant tumors, which are composed of rapidly dividing cells. Such radiation therapy has defects, including weakness or loss of function of normal tissue due thereto, as well as the concern about skin disease on the treated regions. Particularly in children, in which the growth of internal organs is progressing, serious side effects such as delayed cognitive development or bone growth disorders may result. Also, chemotherapy is widely useful in the treatment of breast cancer, lung cancer and testicular cancer by disturbing the replication or metabolism of cancer cells, but suffers from side effects induced by systemic chemotherapy used in the treatment of cancer. Furthermore, side effects associated with chemotherapeutic agents are generally exemplified by dose-limiting toxicity (DLT), which dictates caution upon administration of drugs. For these reasons, side effects attributable to chemotherapeutic agents and radiation therapy are regarded as important problems in the treatment of cancer patients.
Meanwhile, based on reports that breast cancer patients who overexpress, as one of human epidermal growth factor reactors, a tyrosine kinase bonded to the surface of a cell membrane, namely HER2 (Human epidermal growth factor receptor 2), which is present in the cell membrane and includes an extracellular region that binds to a ligand and an endocellular region that causes protein activation, have lower disease-free life expectancy and a higher recurrence rate than normal persons, HER2 was established as a representative breast cancer biomarker. Moreover, with the goal of overcoming the side effects of the existing therapeutic methods, targeted therapy, which attacks signaling pathways related to the proliferation of cancer or inhibits angiogenesis so that cancer cells are starved to death, is receiving attention. Hence, research into HER2-targeted breast cancer treatment methods is ongoing (Korean Patent Application Publication No. 10-2013-0091750), but is still incomplete.